Investigation of Spin Chirality by Polarized Neutrons

The projection of the chiral spin fluctuations on the magnetization is discussed. It is shown that it determines the polarization dependent part of the neutron magnetic scattering. A strong enhancement of this scattering appears near the chiral phase transition in triangular lattice antiferromagnets as well as in all cases when the system is soft and its nonlinearity is important. The example of conventional antiferromagnets is considered. A possibility to observe chiral fluctuations in doped Cu${\mathrm{O}}_2$ planes as a precursor of a proposed chiral state is discussed.